JP2009284277A - Digital still camera with large-sized imager - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital still camera which maintains compactness of a casing when a large-sized imager is mounted especially in the compact digital still camera, and can easily perform adjustment of tilting of the imager required for mounting the large-sized imager. <P>SOLUTION: The digital still camera is characterized in that attaching holes for attaching an imager base with the imager at an outer periphery of a rear end of a fixed cylinder are substantially radially arranged with a main light axis of a lens optical system as the center, through-holes corresponding to the attaching holes are arranged in the vicinity of optional two apexes of a rectangle of the imager held in the imager base and in the vicinity of the center point of a side corresponding to the side of the rectangle of the imager connecting the two apexes, attaching screws are let into the through-holes so as to be screwed in the attaching holes, and thus, the imager base is attached in the fixed cylinder. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a digital still camera having a large image sensor (imager), and more particularly to a compact digital still camera having a large imager.

  In recent years, an image is formed on an image sensor such as a CCD instead of a silver salt camera that forms an image on a consumable film and sensitizes the image to take a photograph. Digital still cameras are widely used.

  An imager such as a CCD is different from a silver salt camera in which a predetermined film such as a 135-size film, for example, must be taken into consideration. In particular, in a compact digital still camera that does not require lens replacement, each model has its own size and number of pixels. What has a characteristic can be employ | adopted. Therefore, the digital still camera can be devised in various ways to reduce the size of the entire housing by designing a lens optical system, a camera housing, an electronic substrate, and the like that are optimal for the characteristics of the imager employed.

  In addition, in the digital still camera, there is a method in which the entire housing is miniaturized by miniaturizing the imager itself.

  However, in a compact digital still camera, when a 1 / 1.8 inch type or 1 / 2.5 inch type imager, which is extremely small compared to a 35 mm film size, is used, a very wide-angle lens optical system must be used. Resulting in a decrease in the dynamic range due to the necessity of further increasing the number of pixels with an extremely small imager. Therefore, since it is difficult to obtain a shallow depth of field with a compact digital still camera, there is a problem that it is not possible to take a photograph expressing a sufficient blur. However, there has been a demand for taking a photograph that expresses sufficient bokeh even with a compact digital still camera, similar to a digital single-lens reflex camera equipped with a large imager.

  In addition, in an imager such as a CCD, regardless of whether the size is extremely small or not, the pixel pitch is inevitably reduced when the number of pixels is increased. Therefore, the permissible circle of confusion required for an imager is smaller than that of a film. . Therefore, in order to mount the imager in a proper posture in the digital still camera, a more severe mounting accuracy is required than the posture accuracy of the film surface of the silver halide camera.

Further, the larger the imager as described above, the inevitably the angle of inclination of the imager with respect to the image forming surface at the periphery, and the higher the imager mounting accuracy, the higher the imager mounting accuracy is required. .

In the mounting structure of the solid-state imaging device described in the cited document 1 (Japanese Patent Laid-Open No. 2001-285722), the mounting structure of the solid-state imaging device capable of mounting the solid-state imaging device with high accuracy without causing surface tilt or positional deviation. Is disclosed. Specifically, this is a structure in which a projecting surface is provided on a metal plate provided with a through-hole, an imaging element is disposed on the projecting surface of the metal plate, and is fixed from the bottom with an adhesive. With this structure, it is possible to stably attach the solid-state image sensor to the optical unit without causing a tilt or a float with respect to the imaging plane of the solid-state image sensor. The purpose of the mounting structure of the solid-state imaging device disclosed in the cited document 1 is to prevent the occurrence of surface tilt and displacement of the solid-state imaging device with respect to the metal plate, and to convert the unit composed of the metal plate and the solid-state imaging device into an optical unit. It is to attach.

In the mounting structure of the image sensor described in Cited Document 2 (Japanese Patent Laid-Open No. 2002-286993), when the image sensor is mounted on the rear end of the lens barrel, the image sensor is directly mounted on the fixed frame itself of the lens barrel. First, an opening is provided at the rear end of the fixed frame, and a holding frame for the image sensor is provided there. By providing the fixed frame and the holding frame for holding the image sensor as separate members, the manufacturing efficiency of the fixed frame, the inspection of the lens optical system, and the replacement of the image sensor are facilitated.

In the tilt adjustment mechanism described in Cited Document 3 (Japanese Patent Laid-Open No. 8-248465), the protrusion of the fixed plate is fixed to the movable plate on which the image pickup device is mounted, with one end of the diagonal line within the effective image pickup range of the image pickup device as the rotation center. The adjustment screw is provided on each of the vertical line and the horizontal line passing through one end of the diagonal line within the effective image pickup range of the image sensor to adjust the tilt in the optical axis direction of the image sensor.
JP 2001-285722 A JP 2002-286993 A JP-A-8-248465

Conventionally, in the imager tilt adjustment when the imager itself is small, since the distance from the support end for adjusting the imager tilt to the adjustment member such as the adjustment screw is short, the sensitivity of the tilt angle to the adjustment amount of the adjustment member is small. It was very expensive. For this reason, the tilt angle of the imager is greatly inclined by a slight adjustment amount, and it is difficult to finely adjust the tilt of the imager.

Further, in order to finely adjust the tilt of the imager, it is disadvantageous in terms of technology and cost to employ an extremely thin washer as an adjustment member that can be finely adjusted. For this reason, the washer cannot be used for adjusting the tilt of the imager, and the tilt adjustment using a spring and a screw is generally used. Moreover, even when adjusting the tilt of the imager using springs and screws, the sensitivity of the tilt angle of the imager to the amount of screw adjustment remains high, so fine adjustment of the tilt of the imager remains difficult. .

In addition, the conventional compact digital camera equipped with a non-replaceable lens barrel is premised on the adoption of an extremely small imager in order to make the case compact. It was provided inside the cylinder. For this reason, when the conventional imager mounting structure and tilt adjustment mechanism are applied to a compact digital camera employing a large imager as it is, the outer shape of the lens barrel may be increased.

In addition, the above cited document is disclosed for the problem of how efficiently and precisely the imager can be adjusted in a conventional digital still camera, but the following problem still remains. ing.

In the mounting structure of the solid-state imaging device described in the cited document 1, it is assumed that the solid-state imaging device itself is attached to the protruding surface of the metal plate so that the solid-state imaging device does not float or fall down. There is no disclosure of a method for correcting floating or falling when a unit composed of elements is attached to an optical unit. The imager tilt adjustment does not depend only on the assembly accuracy, and it is necessary to adjust while actually detecting the necessary adjustment value for each solid. Even if the assembly accuracy is increased, it cannot be said that the imager tilt is eliminated.

In the mounting structure of the image sensor described in the cited document 2, it is possible to replace the image sensor when the image sensor is misaligned, but the attitude of the image sensor cannot be adjusted. For this reason, an image sensor that has been replaced as defective due to a misalignment becomes useless or becomes inefficient even when reused. Further, although it is described that the positional deviation such as the tilt of the image sensor can be easily corrected, a specific method for correcting the tilt of the image sensor by disposing the fixed frame and the holding frame as separate members is disclosed. It has not been.

In the tilt adjustment mechanism described in the cited document 3, it is easy to finely adjust the tilt of the imager by increasing the distance from the protruding portion to the adjustment screw. This increases the size of the fixed plate on which the adjustment screw or the like is provided, and further increases the size of the lens barrel to which the fixed plate is attached. In addition, when the protrusion of the fixed plate is applied to the movable plate to which the image sensor is attached, the concentrated stress may be applied to the effective image pickup range of the image sensor through the fixed plate, and the image sensor has an effective image range. There is a risk of bending inside.

2. Description of the Related Art Conventionally, it has been desired to use a large-sized imager in a compact digital still camera that has not been able to obtain sufficient blur due to the use of an extremely small imager, and the present invention particularly relates to a compact digital still camera. In order to maintain the compactness of the chassis and to make the imager tilt adjustment, which is essential due to the adoption of the large imager, an efficient mechanism in terms of manufacturing and cost. Is an issue.

  In order to solve the above problems, a first invention of the present application includes an imager, an imager base that holds the imager, a lens optical system that couples a subject image to the imager, and a lens mirror that holds the lens optical system. In a digital still camera having a fixed tube, a mounting hole for mounting the imager base is disposed substantially radially around the main optical axis of the lens optical system on the outer periphery of the rear end of the fixed tube. A through hole corresponding to the attachment hole in the vicinity of any two vertices of the rectangle of the imager held in the imager base and in the vicinity of the midpoint of the side opposite to the rectangular side of the imager connecting the two vertices The imager base is attached to the fixed cylinder by arranging a hole, passing a mounting screw through the through hole, and screwing the mounting screw into the mounting hole. It is a digital still camera.

  Further, according to a second invention of the present application, in the first invention, when the imager base is attached to the fixed cylinder by passing the attachment screw through the through hole and screwing into the attachment hole, If necessary to adjust the tilt, adjust the tilt of the imager with the thickness of the adjustment washer by holding one or more adjustment washers between the imager base and the fixed cylinder. This is a digital still camera.

Further, according to a third invention of the present application, in the first invention, the attachment screw is an adjustment screw, the adjustment screw is passed through the through hole, and is screwed into the attachment hole to fix the imager base. When attaching to the cylinder, an adjustment spring is sandwiched between the imager base and the fixed cylinder, so that the amount of the adjustment screw screwed into the fixed cylinder and the expansion / contraction force of the spring cause the imager to collapse. It is a digital still camera characterized by adjusting the camera.

  According to the present invention, it is possible to prevent the outer shape of the lens barrel from becoming large and to easily adjust the collapse of the large imager while adopting a large imager to a compact digital still camera. Specifically, the imager's mounting position is arranged radially outside the lens barrel, reducing the sensitivity of the imager to the amount of tilt adjustment, enabling the use of an adjustment washer, and allowing the imager to fall Can be easily adjusted.

  Hereinafter, embodiments in which the present invention is applied to a compact digital still camera will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same members.

  FIG. 1 is a sectional view of a compact digital still camera having the lens barrel of the present invention. FIG. 2 is a perspective view of the lens barrel of the digital still camera of the present invention. 3 is a rear view of the lens barrel of the digital still camera according to the present invention as seen from the direction of the arrow in FIG. FIG. 4 shows a modification of the embodiment according to the present invention.

  In FIG. 1, 100 is a digital still camera body, 101 is a lens optical system, 102 is a fixed cylinder, 103 is a mounting hole, 104 is an imager base, 105 is an adjustment washer, 106 is a mounting screw, 107 is a dust filter, and 108 is a window. Glass, 109 is a light receiving element, 110 is a ceramic package, 111 is an imager substrate, 112 is a shield plate, 113 is a main substrate, and 114 is an LCD.

  Each lens group constituting the lens optical system 101 is held by a lens frame (not shown), and a lens barrel (not shown) having a cam groove is moved through a roller (not shown) attached to the lens frame. Thus, the lens barrel performs the retracting operation or the extending operation. A mounting hole 103 is provided outside the fixed cylinder 102 in a direction parallel to the optical axis direction. The mounting screw 106 passes through the through hole of the imager base 104 and the adjustment washer 105, and is screwed into the mounting hole 103 for mounting the imager base 104 and the adjustment washer 105 to the fixed cylinder 102. The imager includes a window glass 108, a light receiving element 109, a ceramic package 110, and an imager substrate 111, and is attached to the imager base 104.

  FIG. 2 illustrates how the imager is attached to the lens barrel. The imager is attached to the imager base 104, and is fixed at three points to an attachment hole 103 provided in the fixed barrel 102 of the lens barrel by an attachment screw 106. At that time, an adjustment washer 105 necessary for adjusting the tilt of the imager is sandwiched between the imager base 104 and the fixed cylinder 102, and the tilt of the imager is adjusted by the thickness of the adjustment washer 105.

  A specific method for adjusting the tilt of the imager is as follows. First, the imager base 104 to which the imager is attached is actually attached to the fixed cylinder 102 with the mounting screw 106, and focus is performed over the entire autofocus (AF) driving distance of the lens optical system 101. By driving the lens, at a plurality of arbitrary points on the imager, contrast data targeting a subject at the same distance with respect to each point is scanned. Next, the maximum value of the contrast data in the entire AF driving distance obtained at each point is obtained, and the distances to the corresponding subjects are compared with each other. In order to adjust the tilt of the imager, that is, to correctly correct the distance to the subject that is assumed to be the same distance from the imager at each point, the tilt of the imager is adjusted to each of the mounting screws 106. The adjustment amount required by the adjustment washer 105 is obtained and placed between the imager base 104 and the fixed cylinder 102. As described above, it is possible to adjust the attachment of the imager without falling down.

  The three points for fixing the imager base 104 to the fixed cylinder 102 are arranged radially on the outer periphery of the fixed cylinder 102 as shown in FIG. At the same time, the three points to be fixed are the points on the imager base 104 opposite to the side connecting the two fixed points in the vicinity of any two vertices in the imager rectangle and the two vertices in the imager rectangle. One fixed point in the vicinity of the midpoint. By arranging the three points to be fixed as described above, the main optical axis of the lens optical system 101 can be applied to both the lens barrel 102 having a circular cross section perpendicular to the optical axis direction and the rectangular imager. The imager base 104 can be stably attached to the fixed cylinder 102. Further, the adjustment amount by the adjustment washer 105 at the three fixing points for determining the plane by adjusting the tilt of the imager can be easily adjusted independently, and it becomes easy to efficiently adjust the tilt of the imager. .

  The adjustment member for adjusting the tilt of the imager in the embodiment described above is the adjustment washer 105. The adjustment amount of the adjustment washer 105 required at the three points to be fixed is determined by the amount of tilt at the three points to be fixed calculated based on the contrast data obtained from the imager as described above. The operator only needs to sandwich the necessary adjustment washer 105 between the imager base 104 and the fixed cylinder 102 according to the result, and attach the imager base 104 to the fixed cylinder 102 with the mounting screw 106, so that the inclination of the imager is adjusted. The work is easy.

  FIG. 4 shows, as a modified example of the present invention, the adjustment of the tilting of the imager not by the adjustment washer 105 but by the adjustment spring 115 and the adjustment screw 116.

Conventionally, the imager has been tilted continuously using the adjustment spring 115 and the adjustment screw 116. However, the imager can be greatly tilted even with a small adjustment amount by the adjustment screw 116. It was not easy to adjust the fall.

  However, in the present invention, since the large imager is attached radially to the circular lens barrel cross section and the rectangular imager around the main optical axis of the lens optical system 101, the tilt of the imager is adjusted. The adjustment position to be adjusted can be set far away from the main optical axis of the lens optical system 101, and the sensitivity of the tilt angle to the adjustment amount can be lowered. Therefore, in the method for attaching a large imager according to the present invention, it has become possible to use a washer to adjust the fall of the imager. Similarly, in the present invention, the adjustment of the tilt of the imager by the adjustment spring 115 and the adjustment screw 116 is facilitated because fine adjustment of the adjustment screw is not necessary as compared with the prior art.

As described above, according to the present invention, in a compact digital still camera that employs a large imager that particularly requires adjustment of the imager's tilting, it is possible to prevent the casing from becoming large and to easily adjust the imager's tilting. It becomes possible to provide digital cameras

It is a digital still camera sectional view of the present invention. It is a lens-barrel perspective view of the digital still camera of the present invention. FIG. 3 is a rear view of the lens barrel of the digital still camera of the present invention as viewed from the direction of the arrow in FIG. 2. It is a modification of the Example which concerns on this invention.

Explanation of symbols

100 Digital still camera body 101 Lens optical system 102 Fixed cylinder 103 Mounting hole 104 Imager base 105 Adjustment washer 106 Mounting screw 107 Dust filter 108 Window glass 109 Light receiving element 110 Ceramic package 111 Imager substrate 112 Shield plate 113 Main substrate 114 LCD
115 Adjustment spring 116 Adjustment screw

Claims (3)

In a digital still camera having an imager, an imager base that holds the imager, a lens optical system that couples a subject image to the imager, and a fixed lens barrel that holds the lens optical system,
A mounting hole for mounting the imager base on the outer periphery of the rear end of the fixed cylinder is arranged substantially radially around the main optical axis of the lens optical system,
A through hole corresponding to the mounting hole in the vicinity of any two vertices of the rectangle of the imager held in the imager base, and in the vicinity of the midpoint of the side opposite to the rectangular side of the imager connecting the two vertices Place the hole,
Attaching the imager base to the fixed cylinder by passing a mounting screw through the through hole and screwing into the mounting hole.
This is a digital still camera. When attaching the imager base to the fixed cylinder by threading the mounting screw through the through hole and screwing into the mounting hole,
When necessary to adjust the tilt of the imager, the imager is tilted at the thickness of the adjustment washer by sandwiching one or more adjustment washers between the imager base and the fixed cylinder. The digital still camera according to claim 1, wherein the digital still camera is adjusted. When the mounting screw is an adjustment screw, the adjustment screw is passed through the through hole and screwed into the mounting hole to attach the imager base to the fixed cylinder.
By holding an adjustment spring between the imager base and the fixed cylinder, the tilt of the imager is adjusted by the amount by which the adjustment screw is screwed into the fixed cylinder and the elastic force of the spring. The digital still camera according to claim 1.